'atomise' originates from French, specifically the word 'atomiser', which ultimately comes from New Latin 'atomisare' and Greek 'atomos' where 'a-' meant 'not' and 'tomos' meant 'cut'.

'atomos' in Greek ('ἄτομος') gave New Latin/medieval Latin forms such as 'atomus' and 'atomisare'; French developed 'atomiser' and this was borrowed into English as 'atomise' (modern form).

Initially it meant 'to divide into indivisible parts (atoms)' in the philosophical/physical sense; over time it evolved into the modern, practical sense of 'to reduce to very small particles or a spray' (and also gained figurative uses).